Matching limb protection sleeve for tourniquet cuff

ABSTRACT

Apparatus is provided for protecting a patient&#39;s limb from tourniquet-related injury, comprising: a tourniquet cuff having a length sufficient for encircling a limb protection sleeve applied to a limb at a location having a limb circumference of not less than a predetermined minimum limb circumference and not more than a predetermined maximum limb circumference; limb protection sleeve adapted for applying to the limb at the location, wherein the sleeve has a tubular shape and a tubular circumference predetermined to be less than the predetermined minimum and wherein the sleeve is formed to allow elastic stretching of the tubular shape sufficient to increase the tubular circumference to be substantially equivalent to the limb circumference at the location when the sleeve is applied to the limb, thereby applying a pressure to the limb that is greater than a predetermined minimum pressure and less than a predetermined maximum pressure; and identification means perceptible to a user for providing an indication to the user of the predetermined minimum limb circumference and the predetermined maximum limb circumference.

This patent application is a Continuation In Part of U.S. patentapplication Ser. No. 09/378,034, filed Aug. 20, 1999, now U.S. Pat. No.6,361,548.

FIELD OF THE INVENTION

This invention generally pertains to surgical tourniquets. The inventionparticularly pertains to surgical tourniquet cuffs for encircling andapplying pressure to patients' limbs in order to stop blood flow intothe limbs and to limb protection sleeves matched to the cuffs forinterposing between the limbs and the cuffs to help protect the limbsfrom cuff-related injuries during surgical procedures.

BACKGROUND

Surgical tourniquet cuffs typically are applied to a patient's limb at adesired location and are then pressurized in order to stop the flow ofarterial blood past the cuff, thereby establishing a bloodless filed inthe portion of the limb distal to the cuff. The structure and functionof some typical tourniquet cuffs of the prior art are described byRobinette-Lehmann in U.S. Pat. No. 4,635,635, by Spence in U.S. Pat. No.4,979,953 and by McEwen in U.S. Pat. Nos. 5,454,831 and 5,649,954. Thepressure applied by such prior-art tourniquet cuffs is typicallycontrolled by electronic tourniquet apparatus such as that described byMcEwen in U.S. Pat. No. 4,469,099 by McEwen and Jameson in U.S. Pat. No.5,607,447.

The bloodless surgical field created by a pressurized tourniquet cufffacilitates many types of surgical procedures performed on upper limbsand lower limbs, helps improve the quality and consistency of thesurgical procedures, reduces the need for blood transfusions, andshortens surgical times. In certain kinds of surgical procedures, onlythe portion of the limb distal to the tourniquet cuff is anesthetizedusing a procedure called Bier block anesthesia or Intravenous RegionalAnesthesia (IVRA); in such procedures, the tourniquet cuff performs adual function of keeping the anesthetic agent in the limb and keepingarterial blood out of the limb. Clinical practice involving the use oftourniquets in IVRA was recently summarized in a paper by Henderson etal. entitled “A North American Survey of Intravenous RegionalAnesthesia” published in Anesthesia and Analgesia (1997; 85:858-863).

In an effort to reduce the probability of certain injuries to the softtissues of the limb beneath a pressurized tourniquet cuff, someoperators may elect to apply a soft bandage to the limb beneath thecuff. For example, in “Recommended Practices for Use of the PneumaticTourniquet”, published by the Association of Operating Room Nurses(AORN) in the United States and effective as of Jan. 1, 1999, it isnoted that “The cuff should be applied to the extremity so thatunderlying skin and soft tissue are not unduly traumatized.Manufacturers' instructions may suggest that a soft, wrinkle-freepadding (eg, cotton cast padding, stockinette) be wrapped smoothlyaround the limb as high on the extremity as possible, being careful notto pinch the skin folds where the tourniquet is applied. Once inflatedthe cuff should not be readjusted. Users must note that some tourniquettechnology does not require padding.”

In the prior art, soft bandages that have been used in conjunction withtourniquet cuffs have included sheet padding combined with afluid-impervious layer and an adhesive tab as described by Hubbard etal. in U.S. Pat. No. 4,406,281, as well as cast padding of the typewrapped around a broken limb before a cast is applied. Properapplication of these soft bandages in conjunction with tourniquet cuffusage is very technique-dependent, requiring a trained and experiencedapplicator. Further, some types of padding may release loose fibers whenapplied, and these fibers may enter the surgical field and may clog thehook-and-loop fasteners that are typically used to secure tourniquetcuffs in position around the limb, thereby reducing the effectivestrength of these fasteners and creating a potential hazard. Also, thepadding itself may take on a non-uniform shape around the limb,especially when an overlying tourniquet cuff is inflated. Finally, iftoo much soft bandage is used or if it is applied improperly, thenhazards may arise because the level of pressure required in thetourniquet cuff to stop blood flow past the cuff may increasesubstantially, and the position of the cuff on the limb may becomeunstable after inflation, increasing the likelihood that the cuffposition may change significantly relative to the limb during use.

An alternative to the use of soft bandages and cast padding in the priorart has been to use tubular stockinette between the patient's limb andthe tourniquet cuff. Typically, tubular stockinette is made and suppliedin a wide range of predetermined ‘lay-flat’ widths, knits and materials.Tubular stockinette consists of a knitted textile having a substantiallycylindrical shape in which some of the knitted threads either areelastic or are knitted in a manner that permits elastic stretching ofthe tubular shape. In appearance, tubular stockinette resembles theankle portion of a sock or the leg portion of a nylon stocking. Elasticthreads are included in some types of tubular stockinette to give themstretch and elastic characteristics that are a function of the type andnumber of elastic and non-elastic threads used in the knit and the knitpattern itself. In other types of stockinette that are knitted fromnon-elastic threads, the stretch and elastic characteristics of thestockinette are primarily determined by the type of knit. Two generaladvantages of using tubular stockinette under a tourniquet cuff, incomparison to overlapping soft bandages, are: tubular stockinette doesnot shed loose fibers which can enter the surgical field and clog cufffasteners; and tubular stockinette does not produce as non-uniform ashape around the limb as soft bandages may do.

There are a number of limitations associated with such prior-art tubularstockinette. The most important limitation is that the pressure appliedto the encircled limb by the tubular stockinette may be too high or toolow. If the tubular stockinette is stretched excessively to fit aroundthe limb at the desired cuff location, too high a pressure may result:in such situations, the pressure applied to the limb by the elasticallystretched tubular stockinette may be sufficiently high to stop the flowof venous blood out of the limb and impair the flow of arterial bloodinto the limb.

Because of the concern about residual pressures that might be applied bytubular stockinette, one manufacturer of prior-art tourniquet cuffs andinstruments (Zimmer, Warsaw Ind.) cautions on page 6 of the Operator andService Manual for its A.T.S. 2000 Automatic Tourniquet System that “Asan under padding, a section of stockinette may be used. The deflatedcuff and any underlying bandages should be completely removed as soon astourniquet pressure is released. Even the slightest impedance of venousreturn may lead to congestion and pooling of blood in the operativefield.” Similar cautions and warnings about hazards related to theresidual application of non-pneumatic pressure by underlying paddingsuch as stockinette, as well as tourniquet cuffs, are given by othersuppliers of tourniquet-related products and in the surgical literature.

Alternatively, if the tubular stockinette is not stretched at all, or ifit is not stretched sufficiently at a desired cuff location, then thetubular stockinette may apply no pressure to the underlying limb andinflation of an overlying tourniquet cuff may then produce folding andwrinkling of the tubular stockinette material. This can cause softtissue injuries resulting from pinching, folding and shearing of skinbeneath the tubular stockinette, as well as causing other hazardsarising from local anomalies in the pressure applied to the limb beneaththe tubular stockinette by the inflated cuff and from the increasedinflation pressure that may be required in the cuff to stop blood flow.

One commercial product is known in the prior art that combines tubularstockinette and a single-use tourniquet cuff in a single sterile package(Smith and Nephew Richards Inc., Memphis Tenn.). The tubular stockinetteconsists of a substantially cylindrical length of elasticallystretchable knitted fabric that has been folded back on itself twice, sothat by pulling the tubular stockinette up a limb to a desired cufflocation, the tourniquet cuff can be applied over four layers ofstockinette material. In products inspected by the inventor one commonsleeve size was supplied with the 12″ and 15″ cuff sizes, thus thatspecific sleeve is not matched to a specific cuff, but to two cuffs ofdiffering sizes for differing limb circumference ranges. Similarly, asecond common sleeve size was supplied with the 24″, 34″, and 44″ cuffsizes. The instructions enclosed with the cuff specify that the usershould select a cuff large enough to have at least a suggestedthree-to-four inch overlap. In practical use, if the overlap is lessthan the suggested three-inch minimum at a desired limb location with aselected cuff, then the next larger cuff supplied by the manufacturermust be used. Thus the minimum limb circumference for that next largercuff is effectively equal to the limb circumference that creates lessthan a three-inch overlap in the selected cuff. Accordingly, theeffective limb circumference range of each cuff is (a) a maximum thatallows a three-inch overlap, and (b) a minimum that would allow athree-inch overlap in the next smaller cuff. Over part of these ranges,the stockinette sleeves provided with some of the cuffs inspected aretoo large, i.e. the circumference of the unstretched stockinette isgreater than part of the range of circumferences of limbs on which thecuff may be applied. This is hazardous because, as noted above, theinventor has discovered that if the tubular stockinette is loose and notelastically stretched to apply a small pressure greater than a non-zeropressure threshold (determined in testing by the inventor of the presentinvention to be the minimum pressure at which a visible reduction inwrinkling and pinching was observed) at the desired cuff location on alimb prior to application of the tourniquet cuff, then the applicationand inflation of the cuff over the stockinette will produce folding andwrinkling of the underlying stockinette material, increasing thelikelihood of soft tissue injuries due to pinching, folding and shearingof skin beneath the stockinette, as well as creating other surgical andIVRA-related hazards arising from local anomalies in the pressureapplied to the limb and from the higher pressures that must be appliedonto such stockinette by the encircling tourniquet cuff to stop bloodflow in the underlying limb.

Another similar commercial product is known in the prior art thatcombines tubular stockinette and a single-use tourniquet cuff in asingle sterile package (‘Color Cuff II’, Instrumed Inc., Woodinville,Wash.). The tubular stockinette consists of a substantially cylindricallength of elastically stretchable knitted fabric that has been foldedback on itself once forming a two layer stockinette sleeve. However, aswith the Smith and Nephew Richards product of the prior art, the sleevessupplied with some of the cuffs are not stretched on some limbs withinthe size range of the corresponding cuff. Also as with the Smith andNephew Richards product of the prior art, a sleeve of the same size, andtherefore having exactly the same unstretched circumference, is suppliedwith both the 24″ cuff and the 34″ cuff. Thus that specific sleeve isnot matched to a specific cuff, but to two cuffs of differing sizes fordiffering limb circumference ranges. Instrumed also provides threedifferent sizes of stockinette sleeves, each having a differentcircumference, for use with the six different sizes of non-sterilereusable tourniquet cuffs that it supplies. However no indication isgiven in the documentation supplied to users of the cuffs of anycorrespondence between the sleeve sizes and cuff sizes, and no means isprovided for users to match any specific sleeve sizes to any specificcuff sizes.

The pressure applied by a tubular stockinette to a limb of a givenshape, circumference and tissue composition can be measured using abiomedical pressure transducer such as the one described by McEwen inU.S. Pat. No. 4,869,265. Using such a transducer, it is has been foundin tests conducted by the inventor that pressures from 0 mmHg to morethan 60 mmHg can applied to limbs of varying circumferences and physicalproperties by prior-art tubular stockinettes of varying sizes,materials, knits and designs. For comparison, it has been found that anapplied pressure as low as 30 mmHg can partially or completely obstructvenous blood flow, and that applied pressures lower than 60 mmHg canimpede and partially block arterial blood flow. It is has been found intests conducted by the inventor of the present invention that thepressure of a snugly applied tourniquet cuff can be as high as 25 mmHg.

With both the Smith and Nephew Richards and Instrumed products of theprior art, each different cuff size is indicated by a distinct color onthe product label and on features permanently attached to the cuff. Thesleeves, however, do not have any color or other matching or indicatingfeatures permanently attached. Once the sterile package is opened andthe cuff and sleeve are separated, there is no indication to the user ofthe correct matching between the cuff and sleeve. This can be hazardous.For example, in one Smith and Nephew Richards product inspected by theinventor, an apparently incorrect sleeve size was included in thesterile, sealed package. Testing conducted by the inventor (as describedin the preceding paragraph) revealed that at the maximum limb sizeaccommodated by the cuff, the sleeve included in the package wasextremely tight and applied a hazardous pressure to the limb. In thiscase, indicating means permanently attached to the sleeve may havealerted the user of the inappropriateness of the sleeve for the limbsizes accommodated by the cuff.

In the prior art, there is no known limb protection sleeve that matchesa specific tourniquet cuff for application to limbs havingcircumferences between a minimum and a maximum circumference so that thesleeve, after application to a limb of minimum circumference, stretcheselastically to apply a small pressure greater than a non-zero thresholdto the limb that is effective in reducing wrinkling and pinching of thelimb, and so that the sleeve, after application to a limb of maximumcircumference, applies a pressure to the limb that is less than apredetermined maximum pressure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a pictorial representation of the preferred embodiment appliedto a limb of a surgical patient.

FIG. 2 depicts the inner surfaces of four tourniquet cuffs of similardesign and different sizes.

FIG. 3 shows the outer surface of one of the tourniquet cuffs depictedin FIG. 2.

FIGS. 4 a, 4 b and 4 c show steps in the manufacture of a limbprotection sleeve matching the tourniquet cuff shown in FIG. 3.

FIG. 5 shows four limb protection sleeves that match the four tourniquetcuffs depicted in FIG. 2.

FIGS. 6 a, 6 b and 6 c illustrate steps in a typical selection andapplication of a tourniquet cuff and matching limb protection sleeve toa patient's limb by a user.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The embodiment illustrated is not intended to be exhaustive or limit theinvention to the precise form disclosed. It is chosen and described inorder to explain the principles of the invention and its application andpractical use, and thereby enable others skilled in the art to utilizethe invention.

FIG. 1 depicts the preferred embodiment applied to a limb of a surgicalpatient. Limb protection sleeve 2 has been applied by a user to limb 4along a portion of its length. Inflatable tourniquet cuff 6 is appliedon top of a proximal portion of limb protection sleeve 2 to encircle theportion of sleeve 2 and limb 4 at a location desired by a user. Cuff 6is pneumatically connected to tourniquet instrument 8 through pneumaticport 10 and pneumatic tubing 12. Prior to the commencement of surgery,the portion of sleeve 2 distal to cuff 6 is folded back on top of cuff 6by the user, as depicted in FIG. 6 c. Tourniquet instrument 8 can thensupply gas to tourniquet cuff 6 at a pressure sufficient to stop bloodflow in limb 4 past cuff 6 and sleeve 2 for a time period sufficient forthe performance of a surgical procedure.

FIG. 2 depicts the inner surfaces of tourniquet cuff 6, cuff 14, cuff 16and cuff 18, which are pediatric tourniquet cuffs of different sizesthat are distributed by Delfi Medical Innovations Inc. (Vancouver,Canada). Each of cuffs 6, 14, 16 and 18 is constructed of materials andin a manner generally similar to tourniquet cuffs of the prior art suchas those described by McEwen in U.S. Pat. Nos. 5,454,831 and 5,649,954.

Cuffs 6, 14, 16 and 18 shown in FIG. 2 have overall cuff width and cufflength dimensions as given in the table below. Also, for each of cuffs6, 14, 16 and 18, the table shows the maximum limb circumference and theminimum limb circumference recommended by the distributor in the productliterature and instructions provided for users. To assist users ineasily identifying and differentiating among cuffs, the tie straps ofdifferent cuffs have different colors: cuffs 6, 14 16 and 18 have green,red, blue and black tie straps, respectively, as summarized in thetable.

Cuff no. Overall Overall Recommended Recommended from FIG. 2 Cuff CuffMinimum Limb Maximum Limb (and color Length Width CircumferenceCircumference of tie straps) (inches) (inches) (inches) (inches)  6(green) 17.7 3.50 8.3 15.3 14 (red) 14.9 3.00 6.9 12.5 16 (blue) 10.62.25 4.9 8.3 18 (black) 7.5 1.50 3.5 5.6

FIG. 3 shows the outer surface of cuff 6 that faces away from limb 4when cuff 6 encircles limb 4. The length 24 of cuff 6 is 17.7 inches andthe width 26 of cuff 6 is 3.50 inches. Cuff 6 contains an inflatablechamber 28, the boundary of which can be seen in FIG. 2. Cuff 6 isdesigned to allow a user to encircle a patient's limb 4 at a desiredlocation 30 so that a portion of inflatable chamber 28 of cuff 6overlaps upon itself, and so that the user can secure encircled cuff 6around limb 4 by fully engaging primary cuff fastener 32 to fasteningstrip 34 and by fully engaging secondary cuff fastener 36 to fasteningstrip 34. Complementary hook and loop materials, such as those known inthe prior art as Velcro™, are permanently attached in positions shown inFIGS. 2 and 3 to form primary cuff fastener 32, fastening strip 34 andsecondary cuff fastener 36. Primary cuff fastener 32 and secondary cufffastener 36 are formed of hook material, and fastening strip 34 isformed of loop material. The user may also tie together tie straps 20and 22 as depicted in FIG. 1 to secure cuff end 38. When secured aroundlimb 4 and inflated with gas from tourniquet instrument 8 at asufficient pressure, cuff 6 can apply pressure around encircled limb 4to stop the flow of arterial blood past cuff 6 into limb 4.

Cuff 6 is further designed to encircle limb 4 if limb 4 has a limbcircumference greater than 8.3 inches and less than 15.3 inches atlocation 30, as specified in product literature and instructionsprovided by the distributor for the user. As illustrated in FIGS. 1, 2and 3, when cuff 6 is applied to limb 4 at location 30 having acircumference between the maximum and minimum circumferences recommendedto the user, then the following four conditions occur: (1) a portion ofinflatable chamber 28 overlaps upon itself around limb 4, therebyproducing a uniform application of pressure around limb 4 when chamber28 is inflated, (2) primary cuff fastener 32 can be fully engaged withfastening strip 34 by the user to secure cuff 6 around limb 4, (3)secondary cuff fastener 36 can also be fully engaged with fasteningstrip 34 by the user to secure cuff 6 around limb 4 independently ofprimary cuff fastener 32, and (4) tie straps 20 and 22 can be tiedtogether by the user to secure cuff end 38.

If the circumference of limb 4 at location 30 is greater than themaximum circumference of 15.3 inches recommended to the user, then cuff6 may not safely stop blood flow because of the occurrence of one ormore of the following three conditions: (1) primary cuff fastener 32 maynot filly engage with fastening strip 34; (2) inflatable chamber 28 maynot overlap upon itself around limb 4, thereby producing a non-uniformapplication of pressure around the limb when inflated; and (3) tiestraps 20 and 22 may be obstructed by pneumatic port 10 of cuff 6,thereby preventing straps 20 and 22 from being tied together to securecuff end 38.

Alternatively, if the circumference of limb 4 at location 30 is lessthat the minimum circumference of 8.3 inches, then the efficacy andsafety of cuff 6 may be impaired by the occurrence of one or more of thefollowing four conditions: (1) the width of cuff 6 may be excessiverelative to the length of limb 4, resulting in hazardous application ofpressure by cuff 6 to nerves and soft tissues near the knee or elbowjoints of lower or upper limbs respectively; (2) the width of cuff 6 maybe excessive relative to the length of limb 4, increasing theobstruction of potential surgical sites distal to cuff 6; (3) secondarycuff fastener 36 may not filly engage with fastening strip 34; (4) tiestraps 20 and 22 may be obstructed by pneumatic port 10 of cuff 6,thereby preventing straps 20 and 22 from being tied together to securecuff end 38.

Limb protection sleeve 2 of the preferred embodiment is designed for usewith tourniquet cuff 6 by designing sleeve 2 to have the following fourphysical properties. First, sleeve 2 has a tubular and elasticallystretchable shape, with an unstretched circumference of less than theminimum limb circumference recommended for cuff 6 so that it iselastically stretched when applied to a limb having the minimumrecommended circumference and applies a minimum pressure of 2 mmHg, thelow pressure threshold that the inventor has discovered in experimentsis effective in reducing wrinkling and pinching. The level of 2 mmHg wasdetermined in these tests to be the minimum pressure at which wrinklingand pinching of the tissue beneath cuff 6 began to be visibly reduced.The second physical property of sleeve 2 is that it can be elasticallystretched in a radial direction to a circumference at least equal to themaximum limb circumference recommended for cuff 6. The third property ofsleeve 2 is that, when elastically stretched and applied to a limbhaving the maximum recommended circumference, the maximum pressureapplied to the underlying limb by sleeve 2 is less a predeterminedmaximum pressure threshold of 25 mmHg, determined by the inventor inexperiments to be the maximum pressure normally resulting from the snugapplication of cuff 6 alone to the limb. The fourth physical property ofsleeve 2 is that, when applied to a limb having the maximum recommendedcircumference, the length of sleeve 2 is greater than the width of cuff6, so that a portion of sleeve 2 can be folded over cuff 6 prior to thecommencement of surgery, as shown in FIG. 6 c.

FIGS. 4 a, 4 b and 4 c show how limb protection sleeve 2 is designed andmade to match cuff 6 by having the physical properties described above.First, tubular stockinette 40 shown in FIG. 4 a is produced by knittingtype 18/1 ring spun cotton yarn fiber of natural color using 160 needlesand 25 courses per inch. This results in tubular stockinette 40 having acircumference of 7.0 inches (twice a “layflat” width of about 3.5inches) when not stretched in a radial direction, and having a maximumcircumference of 26 inches (twice a “cross stretch” width of 13 inches)when stretched radially to the maximum. Stockinette 40 is cut to alength of 22.0 inches and folded back onto itself as shown in FIG. 4 b,producing a tube having two layers and a length of 11.0 inches whenunstretched. As depicted in FIG. 4 c, the unfolded end is bias cut. Thisis done with the stockinette laid flat, to remove a piece having length42 equal to 2.5 inches and width 44 equal to half of the layflat widthof the stockinette, as shown in FIG. 4 c. The unfolded end that includesthe bias cut is then serge-sewn with green thread to produce limbprotection sleeve 2 having a green edge 46. As indicated in FIG. 1, thebias cut of sleeve 2 allows sleeve 2 to be positioned as proximally aspossible on limb 4 while still protecting a portion of limb 4 from port10 and tubing 12. Sewn edge 46 increases the stability of dual-layersleeve 2 under matching cuff 6 when cuff 6 is inflated and pressurizedto stop blood flow, and the knit shape of sleeve 2 is compressible inresponse to the application of the pressure by matching cuff 6.

In certain applications (such as adult limbs with less restricted areasof surgical access), port 10 and tubing 12 may be located on the cuffmidline near location 30 (see FIG. 1) rather than in a proximallyprotruding port portion of the cuff. In this case, the proximallyprotruding portion of the sleeve formed by the bias cut of dimensions 42and 44 (shown in FIG. 4 c) is not required and the sleeve may bepositioned on the limb with the serge-sewn edge lying proximal or distalto the cuff. In either orientation the portion of the sleeve extendingdistally from the cuff may be folded over the cuff as shown in FIG. 6 c.Such sleeves are explicitly matched to the corresponding cuff bydesigning the sleeves to have the physical properties described above.To confirm that the design of sleeve 2 of the preferred embodiment, asdescribed above, produces the necessary physical properties, sleeve 2 isapplied to cover a simulated limb having a circumference equal to 15.3inches, the maximum circumference recommended for matching cuff 6. Abiomedical pressure transducer similar to that described by McEwen inU.S. Pat. No. 4,869,265 is inserted between sleeve 2 and the simulatedlimb to measure the applied pressure. The maximum pressure applied bysleeve 2, as measured by the transducer in these design validationtests, is less than 15 mmHg, a pressure known from previous testing doneby the inventor to be substantially less than the maximum non-pneumaticpressure of approximately 25 mmHg that typically can be produced by atourniquet cuff when snugly applied to a limb by a user. Also, sleeve 2is applied to cover a simulated limb having a circumference equal to 8.3inches, the minimum circumference recommended for matching cuff 6, toconfirm that sleeve 2 is elastically stretched after application, thusminimizing any residual wrinkling and irregularities, and to confirmusing the same pressure transducer that the pressure applied to thesimulated limb of minimum circumference by the elastically stretchedsleeve is greater than the predetermined pressure threshold shown tobegin to reduce visible wrinkling and pinching, and that the pressure issubstantially less than 25 mmHg, the predetermined maximum pressurethreshold. It has been demonstrated in testing (for example, seeTredwell S J, Wilmink M, Inkpen K, and McEwen J: “Pediatric Tourniquets:Analysis of cuff/limb interface, current practice, and guideline foruse” Journal of Pediatric Orthopaedics 2001, in press; and McEwen J A,Bailey K, Inkpen K, “Tourniquet safety: What type of padding should beused under the cuff to help prevent skin injuries?”, in review forpublication in AORN Journal) that a stretched sleeve such as sleeve 2 ofthe present invention applies a pressure greater than a predeterminedminimum pressure threshold at the minimum recommended limb circumferencesuch that that wrinkling and pinching is visibly reduced, and less thana maximum pressure threshold at the maximum recommended limbcircumference, and that the application of such a pressure substantiallyreduces wrinkling and pinching of the soft tissues beneath tourniquetcuffs such as cuff 6, as compared to other prior art cuffs applied overloose sleeves, over loose padding, or applied directly on the bare limb.The color of green edge 46 allows a user to visually match sleeve 2 totourniquet cuff 6 having green tie straps 20 and 22. Although a commoncolor is used in the preferred embodiment to associate sleeve 2 and cuff6, it will be appreciated by those skilled in the art that alternatemeans might be used, such as marking numbers, letters or symbolsdirectly on sleeve 2 and cuff 6 or on packages containing each. If cuff6 and sleeve 2 are both designed as disposable medical devices, intendedfor use in only one surgical procedure and disposal after the procedurewithout re-use on another patient, then an alternate way of matchingsleeve 2 and cuff 6 for the user is to package them together at time ofmanufacture, for example by putting them in the same bag or box.

FIG. 5 shows four sizes of limb protection sleeves 2, 48, 50 and 52 thatare matched to tourniquet cuffs 6, 14, 16 and 18 respectively. Sleeves48, 50 and 52 are designed, manufactured and validated as describedabove for sleeve 2, except that each has a different length, unstretchedcircumference, circumference at maximum stretch, and edge color. Sleeve48 matches cuff 14 and is produced by: (a) knitting the same type ofcotton fiber using 124 needles and 23 courses per inch, resulting intubular stockinette having a circumference of 5.0 inches when notstretched in a radial direction, and having a maximum circumference of18.0 inches when stretched radially to the maximum; (b) cutting thestockinette and folding it back onto itself to create a tube having twolayers and a length of 9.5 inches, and (c) bias cutting an unfolded edgeand serging the cut edge with red thread to produce red edge 54 matchingthe red tie straps of cuff 14. Sleeve 50 matches cuff 16 and is producedby: (a) knitting the same type of fiber using 70 needles and 22 coursesper inch, resulting in tubular stockinette having a circumference of 3.0inches when not stretched in a radial direction, and having a maximumcircumference of 13.0 inches when stretched radially to the maximum; (b)cutting the stockinette and folding it back onto itself to create a tubehaving two layers and a length of 8.0 inches, and (c) bias cutting theunfolded edge and serging the cut edge with blue thread to produce blueedge 56 matching the blue tie straps of cuff 6. Sleeve 52 matches cuff18 and is produced by (a) knitting the cotton yarn fiber using 40needles and 21 courses per inch, resulting in tubular stockinette havinga circumference of 1.5 inches when not stretched in a radial direction,and having a maximum circumference of 7.0 inches when stretched radiallyto the maximum; (b) cutting the tubular stockinette and folding it backonto itself to create a tube having two layers and a length of 7.0inches, and (c) bias cutting the unfolded edge and serging the cut edgewith black thread to produce black edge 58 matching the black tie strapsof cuff 18.

For each of limb protection sleeves 2, 48, 50 and 52 shown in FIG. 5,the table below summarizes the respective sleeve length, sleeve edgecolor, unstretched sleeve circumference, maximally stretched sleevecircumference, matching cuff, and the recommended minimum and maximumlimb circumferences for sleeve and matching cuff.

Limb protection Sleeve (in FIG. 5): 2 48 50 52 Sleeve length (inches)11.0 9.5 8.0 7.0 Sleeve edge color Green Red Blue Black Sleevecircumference: Unstretched (in): 7.0 5.0 3.0 1.5 Max. stretch (in): 26.018.0 13.0 7.0 Matching cuff (FIG. 2) 2 14 16 18 Color of tie strapsGreen Red Blue Black Recommended limb Circumferences for Cuff andsleeve: Minimum (inches): 8.3 6.9 4.9 3.5 Maximum (inches): 15.3 12.58.3 5.6

FIGS. 6 a, 6 b and 6 c illustrate steps in a typical selection andapplication of a tourniquet cuff and matching limb protection sleeve tolimb 4 by a user. Prior to these steps, the user first observes thelocation 30 on limb 4 where it is desired to apply a tourniquet cuff andsleeve. The user then selects from the available sizes of cuffs thewidest cuff that can: (a) fully encircle limb 4 at location 30 with aportion of the cuff overlapping upon itself, (b) allow the primary andsecondary cuff fasteners to be fully engaged by the user, and (c) leavea safe distance between the distal edge of the selected cuff and joint60 of limb 4 that is immediately distal location 30. The operatingsurgeon is responsible for determining this safe distance for eachpatient, to prevent injury to exposed nerves, vessels and soft tissuenear joint 60. After the cuff is selected, the matching limb protectionsleeve is selected; in the preferred embodiment, this is done bymatching the color of the tie straps of the cuff to the color of thesewn edge of the sleeve. FIGS. 6 a, 6 b and 6 c indicate that cuff 6 andmatching sleeve 2 have been selected for application at desired location30 on limb 4. The user slides selected sleeve 2 onto limb 4 overlocation 30 as illustrated in FIG. 6 a, and after application assuresthat sleeve 2 is free of wrinkles and that the colored edge 46 of sleeve2 is positioned as shown in FIG. 6 a to help protect limb 4 from port 10and tubing 12. As shown in FIG. 6 b, after application of sleeve 2,selected cuff 6 is wrapped snugly around the proximal portion of sleeve2 and limb 4 at the desired location, while assuring that port 10 ispositioned over sleeve 2 as shown. After snug application of cuff 6 bythe user, the portion of sleeve 2 distal to cuff 6 is folded back overcuff 6 as shown in FIG. 6 c. The operating surgeon then observes cuff 6and sleeve 2 as applied, to assure that there is still a safe distancebetween joint 60 and applied cuff 6 and sleeve 2. The user can thenconnect tubing 12 to port 10 and inflate cuff 6 using tourniquetinstrument 8 to stop blood flow for the performance of a surgicalprocedure. Immediately upon deflation of cuff 6, both cuff 6 and sleeve2 are immediately removed from limb 4 to remove any residual restrictionof blood flow.

It is to be understood that the invention is not to be limited to thedetails herein given but may be modified within the scope of theappended claims.

1. A method for matching components of an apparatus for protecting apatient's limb from tourniquet-related injury, comprising the steps of:selecting a tourniquet cuff component having a length sufficient forencircling a limb at a location having a limb circumference of not lessthan a predetermined minimum limb circumference and not more than apredetermined maximum limb circumference; providing a limb protectionsleeve component that is configured to have a tubular shape and atubular circumference predetermined to be less than the predeterminedminimum limb circumference wherein the sleeve is formed to allow elasticstretching of the tubular shape sufficient to increase the tubularcircumference to be substantially equivalent to the limb circumferencewhen the sleeve is applied to the limb between the cuff and limb,thereby applying a pressure to the limb that is greater than apredetermined minimum pressure and less than a predetermined maximumpressure of 25 mmHg; and matching the selected tourniquet cuff componentand limb protection sleeve component by marking the cuff and sleeve toindicate that those two components match one another.
 2. The method ofclaim 1 wherein the matching step comprises applying a selected color onthe cuff and the same selected color on the sleeve.
 3. The methoddescribed in claim 1 including the step of providing a tourniquetinstrument for inflating the tourniquet cuff at a pressure sufficient tostop blood flow in the encircled limb.
 4. The method of claim 1 whereinproviding the limb protection sleeve includes the step of establishingthe predetermined maximum pressure applied by the sleeve to the limb tobe less than a pressure for partially obstructing venous blood flow inthe limb.
 5. The method of claim 1 wherein the step of establishing thepredetermined maximum pressure applied by the sleeve to the limbincludes measuring the pressure applied by the sleeve to the limb. 6.Apparatus for protecting a patient's limb from tourniquet-relatedinjury, comprising: a tourniquet cuff having a length sufficient forencircling a limb having a limb circumference within a range of not lessthan a predetermined minimum and not more than a predetermined maximum,and wherein the cuff has a first indicium thereon that is indicative ofthat range; a stretchable limb protection sleeve having a tubular shapeand an unstretched circumference that is less than the predeterminedminimum, wherein the sleeve is formed to apply a pressure to the limbthat is greater than a predetermined minimum pressure and less than apredetermined maximum pressure; wherein the cuff has a predeterminedwidth and forms a generally cylindrical shape when encircling the limb,and whereby the sleeve is sized to be substantially wider than the cuffthereby to enable part of the sleeve to underlie the cuff around thelimb while another part of the sleeve is folded over the cuff when thecuff encircles the limb and matching means perceptible to a user formatching the sleeve to the first indicium of the cuff the matching meansincluding a second indicium on the sleeve that corresponds to the firstindicium on the cuff.
 7. The apparatus of claim 6 further comprising aninstrument attached to the cuff for pressurizing the cuff.
 8. Theapparatus of claim 6 wherein the first indicium and the second indiciumare the same color.
 9. Apparatus for protecting a patient's limb fromtourniquet-related injury, comprising: a tourniquet cuff having a lengthsufficient for encircling a limb having a limb circumference within arange of not less than a predetermined minimum and not more than apredetermined maximum, and wherein the cuff has a first indicium thereonthat is indicative of that range; a stretchable limb protection sleevehaving a tubular shape and an unstretched circumference that is lessthan the predetermined minimum, wherein the sleeve is formed to apply apressure to the limb that is greater than a predetermined minimumpressure and less than a predetermined maximum pressure; wherein thesleeve is comprised of two layers, with one layer folded over anotherlayer at a fold edge and so that the edges of the layers away from thefold edge are sewn together at a sewn edge of the sleeve; and matchingmeans perceptible to a user for matching the sleeve to the firstindicium of the cuff the matching means including a second indicium onthe sleeve that corresponds to the first indicium on the cuff.
 10. Theapparatus of claim 9 wherein the second indicium is incorporated intothe sewn edge of the sleeve.